EP0655880A1 - Low voltage circuit for operating a low pressure discharge lamp - Google Patents

Low voltage circuit for operating a low pressure discharge lamp Download PDF

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Publication number
EP0655880A1
EP0655880A1 EP94117877A EP94117877A EP0655880A1 EP 0655880 A1 EP0655880 A1 EP 0655880A1 EP 94117877 A EP94117877 A EP 94117877A EP 94117877 A EP94117877 A EP 94117877A EP 0655880 A1 EP0655880 A1 EP 0655880A1
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EP
European Patent Office
Prior art keywords
lamp
low
circuit arrangement
operating
voltage
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Granted
Application number
EP94117877A
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German (de)
French (fr)
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EP0655880B1 (en
Inventor
Walter Hirschmann
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Osram GmbH
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Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/295—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/05—Starting and operating circuit for fluorescent lamp
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/07—Starting and control circuits for gas discharge lamp using transistors

Definitions

  • the invention relates to a circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to the preamble of protection claim 1.
  • Circuit arrangements of this type are used in commercially available lights, which are powered by a battery and are equipped with a low-pressure discharge lamp. These lights are, for example, hand lights or interior lights for campers and caravans.
  • the circuit arrangements work on the principle of the single-ended flyback converter, which receives a supply voltage of a few volts from the battery and transforms it up to the ignition or operating voltage of the low-pressure discharge lamp.
  • the principle of operation of a single-ended flyback converter is e.g. in the book “Schaltnetzmaschine" by W. Hirschmann / A. Hauenstein, ed. Siemens AG, edition 1990, on pages 45-46.
  • a circuit arrangement based on this principle for operating a low-pressure discharge lamp is disclosed in US Pat. No. 4,973,885.
  • a first secondary winding of the flyback transformer is connected to the base terminal of the flyback transistor via a heatable lamp electrode, while the primary winding of the transformer is integrated in the collector circuit and a second secondary winding is connected to the second lamp electrode.
  • a disadvantage of this circuit arrangement is that the high-frequency alternating current through the heatable lamp electrode does not ensure sufficient electrode preheating. It has been shown that if the heatable lamp electrode is insufficiently preheated, the end of the lamp tends to blacken and has a reduced brightness after a certain operating time. Furthermore, the heating of the electrode filaments in the lamp, which is effective via the feedback winding, causes variable operating currents, which lead to unstable operation of the lamp.
  • the circuit arrangement according to the invention has two diodes, of which a first diode is connected to a connection of the secondary winding of the transformer producing the lamp ignition voltage or the lamp operating voltage and to a first lamp electrode, while the second diode is connected on the one hand to the other connection of the secondary winding and to the primary winding of the Transformer and on the other hand is connected to the second, heatable lamp electrode.
  • the second diode ensures that the heatable lamp electrode is heated by direct current pulses from the primary winding of the transformer during the blocking phase of the flyback converter transistor, premature ignition of the lamp being prevented by the higher damping of the secondary voltage at the beginning of the electrode heating phase.
  • the circuit arrangement according to the invention advantageously contains an additional capacitor which is connected between the unheated lamp electrode and the positive pole of the voltage source or the input capacitor or in parallel with the first diode.
  • This capacitor smoothes the DC voltage pulses and thus improves the operating behavior, in particular the ignition, of the low-pressure discharge lamp. After the lamp has been ignited, the heat output converted in the heatable lamp electrode drops to a low value. With the circuit arrangement according to the invention, the ignition of the lamp can be ensured even at low temperatures.
  • the positive pole of the capacitor C1 or the voltage source is connected to the start of the winding of the primary winding N1 and to the end of the winding of the second secondary winding N3 of the transformer and to the electrode E2 and the capacitor C4.
  • the winding end of the primary winding N1 is led to the collector terminal of the switching transistor T, while the emitter terminal of the transistor T is connected to the negative pole of the input capacitor C1 or the voltage source.
  • the base connection of the transistor T is led to the start of the winding of the second secondary winding N3 of the transformer via a low-pass filter R1, C2 and an adjustable ohmic resistor R2.
  • a capacitor C3 is connected in parallel with the adjustable resistor R2.
  • the low-pass capacitor C2 is parallel to the base-emitter path of the transistor T.
  • a capacitor C5 is arranged parallel to the collector-emitter path of the transistor T, which reduces the flashback voltage and the power loss that occurs.
  • the start of the winding of the secondary winding N2 of the transformer is connected to the collector terminal of the transistor T and to the winding end of the primary winding N1, while the winding end of the secondary winding N2 via the diode D1 and the short-circuited electrode coil E1 of the fluorescent lamp L and via a smoothing capacitor C4 is led to the positive pole of the voltage source.
  • the winding end of the primary winding N1 is also connected to the positive pole of the voltage source via a second diode D2 and the second electrode filament E2 of the lamp L.
  • the second electrode coil E2 is not short-circuited and can therefore be supplied with a heating current.
  • a switch S is integrated in the circuit arrangement, with which the circuit is switched on and off.
  • This circuit arrangement works on the principle of operation of the single-ended flyback converter.
  • the transformer stores energy on the primary side, which it transmits to the lamp L via the secondary winding N2 in the blocking phase.
  • the switching transistor T is controlled by means of the second secondary winding N3, which is fed back to the primary winding N1. Both secondary windings N2, N3 work in opposite directions to the primary winding N1.
  • the flyback converter supplies the lamp L only during the blocking phase of the transistor T, the lamp L is supposed to be operated with unipolar direct current pulses.
  • the diode D1 namely has a certain blocking delay, which allows a brief current flow in the reverse direction, so that a high-frequency alternating current flows through the lamp L.
  • a sufficiently high heating current through the second electrode filament E2 of the lamp L only flows during the blocking phase of the transistor T and also only before the lamp is ignited.
  • the capacitor C4 serves to smooth the ignition voltage and allows the fluorescent lamp to ignite better.
  • the base control of the switching transistor T comprises, in addition to the feedback winding N3 of the transformer, an adjustable ohmic resistor R2 with a capacitor C3 connected in parallel therewith and a low-pass filter consisting of the ohmic resistor R1 and the capacitor C2.
  • the low-pass filter filters out high-frequency components from the base input signal of the transistor T.
  • a suitable dimensioning of the circuit components for this exemplary embodiment is given in Table 1.
  • the lamp L is operated here with an electrical output of approx. 2.5 watts and fed by a 5 volt voltage source.
  • the switching frequency of the transistor T is approximately 55 KHz.
  • the second exemplary embodiment shown in FIG. 2 differs from the first exemplary embodiment only in the capacitor C4 ', which is used instead of the capacitor C4 and is connected in parallel with the first diode D1. All other details as well as the functional principle correspond to the first embodiment.
  • FIG. 3 shows a third embodiment of a circuit arrangement according to the invention.
  • This circuit arrangement essentially corresponds to that of the first exemplary embodiment. Identical components therefore have the same reference numerals in FIG. 3 like the corresponding components in FIG. 1.
  • it contains an infinitely adjustable dimming resistor which allows the fluorescent lamp to be dimmed and a charging socket which enables the rechargeable battery serving as a voltage source to be recharged. With the help of the dimming resistor, the duty cycle of the switching transistor and thus the electrical power supplied to the lamp can be regulated.
  • This circuit arrangement according to the third exemplary embodiment contains as main components a transistor T and a transformer with two secondary windings N2, N3 and ferrite core.
  • Four NiCd battery cells serve as voltage sources, which supply a voltage of approx. 5V.
  • An electrolytic capacitor C1 with a comparatively high capacitance is connected in parallel with the voltage source. This input capacitor C1 prevents the internal resistance which increases with the discharge of the accumulator from having an unfavorable effect on the lamp operation.
  • the positive pole of the capacitor C1 or the voltage source is connected to the winding end of the primary winding N1 and to the beginning of the winding of the second secondary winding or feedback winding N3 of the transformer, as well as to the electrode E2 and to a capacitor C4.
  • the start of the winding of the primary winding N1 is led to the collector terminal of the switching transistor T.
  • the base connection of the transistor T is led to the winding end of the second secondary winding N3 of the transformer via a low pass R1, C2 and an adjustable ohmic resistor R2 and via a variable dimming resistor R3.
  • a capacitor C3 is connected in parallel with the dimming resistor R3 and the adjustable resistor R2.
  • the low-pass capacitor C2 is parallel to the base-emitter path of the transistor T.
  • a capacitor C5 is arranged parallel to the collector-emitter path of the transistor T, which reduces the flashback voltage and the power loss that occurs.
  • the winding end of the secondary winding N2 of the transformer is connected to the collector terminal of the transistor T and to the beginning of the winding of the primary winding N1, while the beginning of the winding of the secondary winding N2 via a diode D1 and the short-circuited electrode coil E1 of the fluorescent lamp L and via the smoothing capacitor C4 to the positive pole of the Voltage source is guided.
  • the start of the winding of the primary winding N1 is also connected to the positive pole of the voltage source via a second diode D2 and the second electrode filament E2 of the lamp L.
  • the second electrode coil E2 is not short-circuited and can therefore be supplied with a heating current.
  • a switch S is integrated in the circuit arrangement, with which the circuit is switched on and off.
  • the circuit arrangement contains a charging socket B, which allows the battery to be recharged.
  • the connection 1 of the charging socket B is connected via a diode D3 and an ohmic resistor R4 to the positive pole of the voltage source and via a light-emitting diode D4 and via an ohmic resistor R5 to the minus pole of the input capacitor C1.
  • the connection 2 of the charging socket B is connected to the emitter connection of the transistor T, while the connection 3 of the charging socket B is led to the negative pole of the voltage source and to the negative pole of the input capacitor C1.
  • the connections 2 and 3 of the charging socket B are connected to one another in an electrically conductive manner, so that the emitter of the transistor T is present at the negative pole of the voltage source.
  • the LED D4 lights up and the energy supply to the lamp L does not take place even when the switch S is closed.
  • the electrically conductive connection between the terminals 2 and 3 of the charging socket B and thus the connection between the emitter of the switching transistor T and the negative pole of the voltage source is interrupted.
  • the circuit works according to the same functional principle as that of the first exemplary embodiment already explained.

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  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

The invention relates to a circuit arrangement for operating a low-pressure discharge lamp (L) at a low-voltage source. It operates in accordance with the principle of the single-ended flyback converter and has, in the direction of the lamp (L), two diodes (D1, D2), the diode (D2) serving to preheat the lamp electrode (E2). The diode (D1) is connected between the secondary winding (N2) of the transformer and the lamp electrode (E1), and the other diode (D2) is connected between the primary winding (N1) and the lamp electrode (E2). An additional capacitor (C4) improves the starting of the lamp. <IMAGE>

Description

Die Erfindung betrifft eine Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle gemäß dem Oberbegriff des Schutzanspruchs 1.The invention relates to a circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to the preamble of protection claim 1.

Derartige Schaltungsanordnungen werden in handelsüblichen, von einer Batterie gespeisten Leuchten, die mit einer Niederdruckentladungslampe ausgestattet sind, verwendet. Bei diesen Leuchten handelt es sich beispielsweise um Handleuchten oder um Innenraumleuchten für Wohnmobile und Wohnwagen. Die Schaltungsanordnungen arbeiten nach dem Prinzip des Eintakt-Sperrwandlers, der von der Batterie eine Versorgungsspannung von wenigen Volt erhält und diese auf die Zünd- bzw. Betriebsspannung der Niederdruckentladungslampe hochtransformiert. Das Funktionsprinzip eines Eintakt-Sperrwandlers ist z.B. in dem Buch "Schaltnetzteile" von W. Hirschmann/ A. Hauenstein, Hrsg. Siemens AG, Auflage 1990, auf den Seiten 45-46 beschrieben. Eine auf diesem Prinzip beruhende Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe ist in dem Patent US 4 973 885 offenbart.Circuit arrangements of this type are used in commercially available lights, which are powered by a battery and are equipped with a low-pressure discharge lamp. These lights are, for example, hand lights or interior lights for campers and caravans. The circuit arrangements work on the principle of the single-ended flyback converter, which receives a supply voltage of a few volts from the battery and transforms it up to the ignition or operating voltage of the low-pressure discharge lamp. The principle of operation of a single-ended flyback converter is e.g. in the book "Schaltnetzteile" by W. Hirschmann / A. Hauenstein, ed. Siemens AG, edition 1990, on pages 45-46. A circuit arrangement based on this principle for operating a low-pressure discharge lamp is disclosed in US Pat. No. 4,973,885.

Bei dieser Schaltungsanordnung ist eine erste Sekundärwicklung des Sperrwandler-Transformators über eine heizbare Lampenelektrode mit dem Basisanschluß des Sperrwandler-Transistors verbunden, während die Primärwicklung des Transformators in den Kollektorkreis integriert und eine zweite Sekundärwicklung mit der zweiten Lampenelektrode verbunden ist.In this circuit arrangement, a first secondary winding of the flyback transformer is connected to the base terminal of the flyback transistor via a heatable lamp electrode, while the primary winding of the transformer is integrated in the collector circuit and a second secondary winding is connected to the second lamp electrode.

Ein Nachteil dieser Schaltungsanordnung besteht darin, daß der hochfrequente Wechselstrom durch die heizbare Lampenelektrode keine ausreichende Elektrodenvorheizung gewährleistet. Es hat sich gezeigt, daß bei ungenügender Vorheizung der heizbaren Lampenelektrode das Lampenende zur Schwärzung neigt und nach einer gewissen Betriebszeit eine verringerte Helligkeit aufweist. Ferner verursacht die über die Rückkopplungswicklung wirksame Heizung der Elektrodenwendeln in der Lampe veränderliche Betriebströme, die zu einem unruhigen Betrieb der Lampe führen.A disadvantage of this circuit arrangement is that the high-frequency alternating current through the heatable lamp electrode does not ensure sufficient electrode preheating. It has been shown that if the heatable lamp electrode is insufficiently preheated, the end of the lamp tends to blacken and has a reduced brightness after a certain operating time. Furthermore, the heating of the electrode filaments in the lamp, which is effective via the feedback winding, causes variable operating currents, which lead to unstable operation of the lamp.

Es ist die Aufgabe der Erfindung, eine Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle bereitzustellen, die eine ausreichende Vorheizung einer Lampenelektrode gewährleistet, und über die Lampenlebensdauer hohe Schaltzahlen ermöglicht.It is the object of the invention to provide a circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source Adequate preheating of a lamp electrode is guaranteed and high switching numbers are possible over the life of the lamp.

Diese Aufgabe wird erfindungsgemäß durch die kennzeichnenden Merkmale des Schutzanspruchs 1 gelöst. Besonders vorteilhafte Ausführungen der Erfindung sind in den Unteransprüchen beschrieben.This object is achieved by the characterizing features of claim 1. Particularly advantageous embodiments of the invention are described in the subclaims.

Die erfindungsgemäße Schaltungsanordnung besitzt zwei Dioden, von denen eine erste Diode mit einem Anschluß der die Lampenzündspannung bzw. die Lampenbetriebsspannung erzeugenden Sekundärwicklung des Transformators und mit einer ersten Lampenelektrode verbunden ist, während die zweite Diode einerseits mit dem anderen Anschluß der Sekundärwicklung sowie mit der Primärwicklung des Transformators und andererseits mit der zweiten, heizbaren Lampenelektrode verbunden ist. Die zweite Diode gewährleistet, daß die heizbare Lampenelektrode während der Sperrphase des Sperrwandler-Transistors von der Primärwicklung des Transformators mit Gleichstromimpulsen geheizt wird, wobei eine vorzeitige Zündung der Lampe durch die zu Beginn der Elektrodenheizphase höhere Dämpfung der Sekundärspannung verhindert wird.The circuit arrangement according to the invention has two diodes, of which a first diode is connected to a connection of the secondary winding of the transformer producing the lamp ignition voltage or the lamp operating voltage and to a first lamp electrode, while the second diode is connected on the one hand to the other connection of the secondary winding and to the primary winding of the Transformer and on the other hand is connected to the second, heatable lamp electrode. The second diode ensures that the heatable lamp electrode is heated by direct current pulses from the primary winding of the transformer during the blocking phase of the flyback converter transistor, premature ignition of the lamp being prevented by the higher damping of the secondary voltage at the beginning of the electrode heating phase.

Vorteilhafterweise enthält die erfindungsgemäße Schaltungsanordnung einen zusätzlichen Kondensator, der zwischen die unbeheizte Lampenelektrode und den Pluspol der Spannungsquelle bzw. des Eingangskondensators oder aber parallel zur ersten Diode geschaltet ist. Dieser Kondensator sorgt für eine Glättung der Gleichspannungsimpulse und verbessert damit das Betriebsverhalten, insbesondere die Zündung, der Niederdruckentladungslampe. Nach der Zündung der Lampe geht die in der heizbaren Lampenelektrode umgesetzte Heizleistung auf einen geringen Wert zurück. Mit der erfindungsgemäßen Schaltungsanordnung kann die Zündung der Lampe auch bei tiefen Temperaturen gewährleistet werden.The circuit arrangement according to the invention advantageously contains an additional capacitor which is connected between the unheated lamp electrode and the positive pole of the voltage source or the input capacitor or in parallel with the first diode. This capacitor smoothes the DC voltage pulses and thus improves the operating behavior, in particular the ignition, of the low-pressure discharge lamp. After the lamp has been ignited, the heat output converted in the heatable lamp electrode drops to a low value. With the circuit arrangement according to the invention, the ignition of the lamp can be ensured even at low temperatures.

Die Erfindung wird nachstehend anhand dreier Ausführungsbeispiele näher erläutert. Es zeigen:

Figur 1
ein erstes Ausführungsbeispiel einer erfindungsgemäßen Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle
Figur 2
ein zweites Ausführungsbeispiel einer erfindungsgemäßen Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle
Figur 3
ein drittes Ausführungsbeispiel einer erfindungsgemäßen Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle
Die Schaltungsanordnung gemäß des ersten Ausführungsbeispiels ist zum Betrieb einer Handleuchte, die mit einer U-förmigen Leuchtstofflampe ausgestattet ist, vorgesehen. Sie arbeitet nach dem Prinzip des Eintakt-Sperrwandlers und enthält als Hauptbestandteile einen Transistor T sowie einen Transformator mit zwei Sekundärwicklungen N2, N3 und Ferritkern. Als Spannungsquelle dient eine Batterie oder ein Akkumulator. Parallel zur Spannungsquelle ist ein Elektrolytkondensator C1 mit einer vergleichsweise hohen Kapazität geschaltet. Dieser Eingangskondensator C1 lädt sich auf die Batteriespannung auf und verhindert, daß sich der mit der Entladung der Batterie zunehmende Innenwiderstand ungünstig auf den Lampenbetrieb auswirkt, d.h., daß die Lampenhelligkeit mit zunehmender Entladung der Batterie zu sehr absinkt..The invention is explained in more detail below with the aid of three exemplary embodiments. Show it:
Figure 1
a first embodiment of a circuit arrangement according to the invention for operating a low-pressure discharge lamp on a low-voltage voltage source
Figure 2
a second embodiment of a circuit arrangement according to the invention for operating a low-pressure discharge lamp on a low-voltage voltage source
Figure 3
a third embodiment of a circuit arrangement according to the invention for operating a low-pressure discharge lamp on a low-voltage voltage source
The circuit arrangement according to the first exemplary embodiment is provided for operating a hand lamp which is equipped with a U-shaped fluorescent lamp. It works on the principle of the single-ended flyback converter and contains the main components of a transistor T and a transformer with two secondary windings N2, N3 and ferrite core. A battery or an accumulator serves as the voltage source. An electrolytic capacitor C1 with a comparatively high capacitance is connected in parallel with the voltage source. This input capacitor C1 charges up to the battery voltage and prevents the internal resistance which increases with the discharge of the battery from having an adverse effect on the lamp operation, ie that the lamp brightness falls too much with increasing discharge of the battery.

Der Pluspol des Kondensators C1 bzw. der Spannungsquelle ist mit dem Wicklungsanfang der Primärwicklung N1 und mit dem Wicklungsende der zweiten Sekundärwicklung N3 des Transformators sowie mit der Elektrode E2 und mit dem Kondensator C4 verbunden. Das Wicklungsende der Primärwicklung N1 ist zum Kollektoranschluß des Schalttransistors T geführt, während der Emitteranschluß des Transistors T an den Minuspol des Eingangskondensators C1 bzw. der Spannungsquelle angeschlossen ist. Der Basisanschluß des Transistors T ist über einen Tiefpaß R1, C2 und über einen einstellbaren ohmschen Widerstand R2 zum Wicklungsanfang der zweiten Sekundärwicklung N3 des Transformators geführt. Parallel zum einstellbaren Widerstand R2 ist eine Kapazität C3 geschaltet. Der Tiefpaßkondensator C2 liegt parallel zur Basis-Emitter-Strecke des Transistors T. Parallel zur Kollektor-Emitter-Strecke des Transistors T ist ein Kondensator C5 angeordnet, der die Rückschlagspannung und die auftretende Verlustleistung verringert. Der Wicklungsanfang der Sekundärwicklung N2 des Transformators ist mit dem Kollektoranschluß des Transistors T und mit dem Wicklungsende der Primärwicklung N1 verbunden, während das Wicklungsende der Sekundärwicklung N2 über die Diode D1 und über die kurzgeschlossene Elektrodenwendel E1 der Leuchtstofflampe L sowie über einen Glättungskondensator C4 zum Pluspol der Spannungsquelle geführt ist. Das Wicklungsende der Primärwicklung N1 ist über eine zweite Diode D2 sowie über die zweite Elektrodenwendel E2 der Lampe L ebenfalls mit dem Pluspol der Spannungsquelle verbunden. Im Gegensatz zur ersten Elektrodenwendel E1 ist die zweite Elektrodenwendel E2 nicht kurzgeschlossen und kann daher mit einem Heizstrom beaufschlagt werden. Zwischen dem Pluspol der Spannungsquelle und dem Pluspol des Eingangskondensators C1 ist ein Schalter S in die Schaltungsanordnung integriert, mit dem die Schaltung ein- bzw. ausgeschaltet wird.The positive pole of the capacitor C1 or the voltage source is connected to the start of the winding of the primary winding N1 and to the end of the winding of the second secondary winding N3 of the transformer and to the electrode E2 and the capacitor C4. The winding end of the primary winding N1 is led to the collector terminal of the switching transistor T, while the emitter terminal of the transistor T is connected to the negative pole of the input capacitor C1 or the voltage source. The base connection of the transistor T is led to the start of the winding of the second secondary winding N3 of the transformer via a low-pass filter R1, C2 and an adjustable ohmic resistor R2. A capacitor C3 is connected in parallel with the adjustable resistor R2. The low-pass capacitor C2 is parallel to the base-emitter path of the transistor T. A capacitor C5 is arranged parallel to the collector-emitter path of the transistor T, which reduces the flashback voltage and the power loss that occurs. The start of the winding of the secondary winding N2 of the transformer is connected to the collector terminal of the transistor T and to the winding end of the primary winding N1, while the winding end of the secondary winding N2 via the diode D1 and the short-circuited electrode coil E1 of the fluorescent lamp L and via a smoothing capacitor C4 is led to the positive pole of the voltage source. The winding end of the primary winding N1 is also connected to the positive pole of the voltage source via a second diode D2 and the second electrode filament E2 of the lamp L. In contrast to the first electrode coil E1, the second electrode coil E2 is not short-circuited and can therefore be supplied with a heating current. Between the positive pole of the voltage source and the positive pole of the input capacitor C1, a switch S is integrated in the circuit arrangement, with which the circuit is switched on and off.

Diese Schaltungsanordnung arbeitet nach dem Funktionsprinzip des Eintakt-Sperrwandlers. Während der Leitphase des Transistors T speichert der Transformator primärseitig Energie, die er in der Sperrphase über die Sekundärwicklung N2 an die Lampe L abgibt. Der Schalttransistor T wird mittels der zweiten, zur Primärwicklung N1 rückgekoppelten Sekundärwicklung N3 gesteuert. Beide Sekundärwicklungen N2, N3 arbeiten gegensinnig zur Primärwicklung N1.This circuit arrangement works on the principle of operation of the single-ended flyback converter. During the conducting phase of the transistor T, the transformer stores energy on the primary side, which it transmits to the lamp L via the secondary winding N2 in the blocking phase. The switching transistor T is controlled by means of the second secondary winding N3, which is fed back to the primary winding N1. Both secondary windings N2, N3 work in opposite directions to the primary winding N1.

Nach dem Einschalten des Schalters S fließt durch die Rückkopplungswicklung N3 des Transformators ein Strom, der zum Durchschalten des Transistors T führt und einen anwachsenden Strom durch die Primärwicklung N1 sowie über die nun leitfähige Kollektor-Enlitter-Strecke des Transistors T verursacht. Hat der Stromfluß durch die Primärwicklung N1 seinen Maximalwert erreicht, dann wird in der Rückkopplungswicklung N3 eine gegensinnig gepolte Spannung induziert, die den Transistor T sperrt. Nach dem Abklingen des Induktionvorganges wird der Transistor T mittels der Rückkopplung zwischen der Primär- N1 und der Rückkopplungswicklung N3 wieder eingeschaltet. Es beginnt ein neuer Schaltzyklus.After the switch S has been switched on, a current flows through the feedback winding N3 of the transformer, which leads to the transistor T being turned on and causes an increasing current through the primary winding N1 and via the now conductive collector-enlitter path of the transistor T. If the current flow through the primary winding N1 has reached its maximum value, a voltage which is polarized in opposite directions and which blocks the transistor T is induced in the feedback winding N3. After the induction process has subsided, the transistor T is switched on again by means of the feedback between the primary N1 and the feedback winding N3. A new switching cycle begins.

Beim Sperren des Transistors T wird in der ersten Sekundärwicklung N2 ebenfalls eine Induktionsspannung hervorgerufen, die die für die Lampe L erforderliche Zündbzw. Betriebsspannung erzeugt. Die Diode D1 und der geringe Widerstand der noch kalten Lampenelektrode E2 verhindern ein sofortiges Durchzünden der Lampe L. Zunächst fließt durch die Diode D2 und die Elektrodenwendel E2 der Lampe L ein von der Primärwicklung N1 gespeister Heizstrom. Mit wachsender Aufheizung der Lampenelektrode E2 nimmt ihr ohmscher Widerstand zu, wodurch auch die in der Sekundärwicklung N2 induzierte Spannung ansteigt, bis zwischen den Lampenelektroden E1, E2 die Zündspannung von ca. 700 Volt erreicht wird und die Lampe L durchzündet. Die Elektrodenheizphase erstreckt sich über mehrere Schaltzyklen des Transistors T und dauert ca. 0,25 sec. Die Schaltfrequenz des Transistors T liegt oberhalb von 20 KHz.When the transistor T is turned off, an induction voltage is likewise produced in the first secondary winding N2, which voltage increases the ignition or ignition required for the lamp L. Operating voltage generated. The diode D1 and the low resistance of the still cold lamp electrode E2 prevent the lamp L from immediately igniting. First, a heating current fed by the primary winding N1 flows through the diode D2 and the electrode coil E2 of the lamp L. As the lamp electrode E2 heats up, its ohmic resistance increases, as a result of which the voltage induced in the secondary winding N2 also increases until the ignition voltage of approximately 700 volts is reached between the lamp electrodes E1, E2 and the lamp L ignites. The electrode heating phase extends over several switching cycles of the Transistor T and takes about 0.25 sec. The switching frequency of transistor T is above 20 KHz.

Nach dem Durchzünden der Lampe L liegt an ihr nur noch die deutlich geringere Betriebsspannung von ca. 110 Volt an. Da der Sperrwandler die Lampe L nur während der Sperrphase des Transistors T versorgt, wird die Lampe L vermeintlich mit unipolaren Gleichstromimpulsen betrieben. Die Diode D1 besitzt nämlich eine gewisse Sperrverzögerung, die einen kurzzeitigen Stromfluß auch in Sperrichtung erlaubt, sodaß durch die Lampe L ein hochfrequenter Wechselstrom fließt. Ein ausreichend hoher Heizstrom durch die zweite Elektrodenwendel E2 der Lampe L fließt nur während der Sperrphase des Transistors T und auch nur vor dem Zünden der Lampe. Der Kondensator C4 dient zur Glättung der Zündspannung und erlaubt ein besseres Durchzünden der Leuchtstofflampe.After the lamp L has been ignited, only the significantly lower operating voltage of approximately 110 volts is present at it. Since the flyback converter supplies the lamp L only during the blocking phase of the transistor T, the lamp L is supposed to be operated with unipolar direct current pulses. The diode D1 namely has a certain blocking delay, which allows a brief current flow in the reverse direction, so that a high-frequency alternating current flows through the lamp L. A sufficiently high heating current through the second electrode filament E2 of the lamp L only flows during the blocking phase of the transistor T and also only before the lamp is ignited. The capacitor C4 serves to smooth the ignition voltage and allows the fluorescent lamp to ignite better.

Die Basisansteuerung des Schalttransistors T umfaßt neben der Rückkopplungswicklung N3 des Transformators einen einstellbaren ohmschen Widerstand R2 mit einem parallel dazu geschalteten Kondensator C3 und einen Tiefpaß, der aus dem ohmschen Widerstand R1 und der Kapazität C2 besteht. Der Tiefpaß filtert hochfrequente Anteile aus dem Basiseingangssignal des Transistors T heraus. Mit Hilfe des Basisvorwiderstandes R2 und der dazu parallel geschalteten Kapazität C3 kann, bei geeigneter Dimensionierung die Schaltfrequenz des Transistors auf einen Sollwert eingestellt werden.The base control of the switching transistor T comprises, in addition to the feedback winding N3 of the transformer, an adjustable ohmic resistor R2 with a capacitor C3 connected in parallel therewith and a low-pass filter consisting of the ohmic resistor R1 and the capacitor C2. The low-pass filter filters out high-frequency components from the base input signal of the transistor T. With the aid of the basic series resistor R2 and the capacitor C3 connected in parallel thereto, the switching frequency of the transistor can be set to a desired value if the dimensions are suitable.

Eine geeignete Dimensionierung der Schaltungsbauteile für dieses Ausführungsbeispiel ist in der Tabelle 1 angegeben. Die Lampe L wird hier mit einer elektrischen Leistung von ca. 2,5 Watt betrieben und von einer 5-Volt-Spannungsquelle gespeist. Die Schaltfrequenz des Transistors T beträgt hier ca. 55 KHz.A suitable dimensioning of the circuit components for this exemplary embodiment is given in Table 1. The lamp L is operated here with an electrical output of approx. 2.5 watts and fed by a 5 volt voltage source. The switching frequency of the transistor T is approximately 55 KHz.

Das in Figur 2 dargestellte zweite Ausführungsbeispiel unterscheidet sich vom ersten Ausführungsbeispiel nur durch den Kondensator C4', der anstelle des Kondensators C4 eingesetzt und parallel zur ersten Diode D1 geschaltet ist. Alle anderen Details sowie auch das Funktionsprinzip entsprechen dem ersten Ausführungsbeispiel.The second exemplary embodiment shown in FIG. 2 differs from the first exemplary embodiment only in the capacitor C4 ', which is used instead of the capacitor C4 and is connected in parallel with the first diode D1. All other details as well as the functional principle correspond to the first embodiment.

Figur 3 zeigt ein drittes Ausführungsbeispiel einer erfindungsgemäßen Schaltungsanordnung. Diese Schaltungsanordnung entspricht im wesentlichen der des ersten Ausführungsbeispiels. Identische Bauteile tragen daher in der Figur 3 dieselben Bezugszeichen wie die entsprechenden Bauteile in der Figur 1. Zusätzlich enthält sie allerdings einen stufenlos einstellbaren Dimmwiderstand, der ein Dimmen der Leuchtstofflampe erlaubt und eine Ladebuchse, die ein Nachladen des als Spannungsquelle dienenden Akkumulators ermöglicht. Mit Hilfe des Dimmwiderstandes kann das Tastverhältnis des Schalttransistors und damit die der Lampe zugeführte elektrische Leistung reguliert werden.Figure 3 shows a third embodiment of a circuit arrangement according to the invention. This circuit arrangement essentially corresponds to that of the first exemplary embodiment. Identical components therefore have the same reference numerals in FIG. 3 like the corresponding components in FIG. 1. In addition, however, it contains an infinitely adjustable dimming resistor which allows the fluorescent lamp to be dimmed and a charging socket which enables the rechargeable battery serving as a voltage source to be recharged. With the help of the dimming resistor, the duty cycle of the switching transistor and thus the electrical power supplied to the lamp can be regulated.

Diese Schaltungsanordnung gemäß des dritten Ausführungsbeispiels enthält als Hauptbestandteile einen Transistor T sowie einen Transformator mit zwei Sekundärwicklungen N2, N3 und Ferritkern. Als Spannungsquelle dienen vier NiCd-Akkumulatorzellen, die eine Spannung von ca. 5V liefern. Parallel zur Spannungsquelle ist ein Elektrolytkondensator C1 mit einer vergleichsweise hohen Kapazität geschaltet. Dieser Eingangskondensator C1 verhindert, daß sich der mit der Entladung des Akkumulators zunehmende Innenwiderstand ungünstig auf den Lampenbetrieb auswirkt.This circuit arrangement according to the third exemplary embodiment contains as main components a transistor T and a transformer with two secondary windings N2, N3 and ferrite core. Four NiCd battery cells serve as voltage sources, which supply a voltage of approx. 5V. An electrolytic capacitor C1 with a comparatively high capacitance is connected in parallel with the voltage source. This input capacitor C1 prevents the internal resistance which increases with the discharge of the accumulator from having an unfavorable effect on the lamp operation.

Der Pluspol des Kondensators C1 bzw. der Spannungsquelle ist mit dem Wicklungsende der Primärwicklung N1 und mit dem Wicklungsanfang der zweiten Sekundärwicklung bzw. Rückkopplungswicklung N3 des Transformators sowie mit der Elektrode E2 und mit einem Kondensator C4 verbunden. Der Wicklungsanfang der Primärwicklung N1 ist zum Kollektoranschluß des Schalttransistors T geführt. Der Basisanschluß des Transistors T ist über einen Tiefpaß R1, C2 und über einen einstellbaren ohmschen Widerstand R2 sowie über einen variablen Dimmwiderstand R3 zum Wicklungsende der zweiten Sekundärwicklung N3 des Transformators geführt. Parallel zum Dimmwiderstand R3 und zum einstellbaren Widerstand R2 ist eine Kapazität C3 geschaltet. Der Tiefpaßkondensator C2 liegt parallel zur Basis-Emitter-Strekke des Transistors T. Parallel zur Kollektor-Emitter-Strecke des Transistors T ist ein Kondensator C5 angeordnet, der die Rückschlagspannung und die auftretende Verlustleistung verringert. Das Wicklungsende der Sekundärwicklung N2 des Transformators ist mit dem Kollektoranschluß des Transistors T und mit dem Wicklungsanfang der Primärwicklung N1 verbunden, während der Wicklungsanfang der Sekundärwicklung N2 über eine Diode D1 und über die kurzgeschlossene Elektrodenwendel E1 der Leuchtstofflampe L sowie über den Glättungskondensator C4 zum Pluspol der Spannungsquelle geführt ist. Der Wicklungsanfang der Primärwicklung N1 ist über eine zweite Diode D2 sowie über die zweite Elektrodenwendel E2 der Lampe L ebenfalls mit dem Pluspol der Spannungsquelle verbunden. Im Gegensatz zur ersten Elektrodenwendel E1 ist die zweite Elektrodenwendel E2 nicht kurzgeschlossen und kann daher mit einem Heizstrom beaufschlagt werden. Zwischen dem Pluspol der Spannungsquelle und dem Pluspol des Eingangskondensators C1 ist ein Schalter S in die Schaltungsanordnung integriert, mit dem die Schaltung ein- bzw. ausgeschaltet wird.The positive pole of the capacitor C1 or the voltage source is connected to the winding end of the primary winding N1 and to the beginning of the winding of the second secondary winding or feedback winding N3 of the transformer, as well as to the electrode E2 and to a capacitor C4. The start of the winding of the primary winding N1 is led to the collector terminal of the switching transistor T. The base connection of the transistor T is led to the winding end of the second secondary winding N3 of the transformer via a low pass R1, C2 and an adjustable ohmic resistor R2 and via a variable dimming resistor R3. A capacitor C3 is connected in parallel with the dimming resistor R3 and the adjustable resistor R2. The low-pass capacitor C2 is parallel to the base-emitter path of the transistor T. A capacitor C5 is arranged parallel to the collector-emitter path of the transistor T, which reduces the flashback voltage and the power loss that occurs. The winding end of the secondary winding N2 of the transformer is connected to the collector terminal of the transistor T and to the beginning of the winding of the primary winding N1, while the beginning of the winding of the secondary winding N2 via a diode D1 and the short-circuited electrode coil E1 of the fluorescent lamp L and via the smoothing capacitor C4 to the positive pole of the Voltage source is guided. The start of the winding of the primary winding N1 is also connected to the positive pole of the voltage source via a second diode D2 and the second electrode filament E2 of the lamp L. In contrast to the first electrode coil E1, the second electrode coil E2 is not short-circuited and can therefore be supplied with a heating current. Between the positive pole of the voltage source and the positive pole of the input capacitor C1, a switch S is integrated in the circuit arrangement, with which the circuit is switched on and off.

Ferner enthält die Schaltungsanordnung eine Ladebuchse B, die ein Nachladen des Akkumulators erlaubt. Der Anschluß 1 der Ladebuchse B ist über eine Diode D3 und einen ohmschen Widerstand R4 mit dem Pluspol der Spannungsquelle und über eine Leuchtdiode D4 sowie über einen ohmschen Widerstand R5 mit dem Minuspol des Eingangskondensators C1 verbunden. Der Anschluß 2 der Ladebuchse B ist an den Emitteranschluß des Transistors T angeschlossen, während der Anschluß 3 der Ladebuchse B zum Minuspol der Spannungsquelle und zum Minuspol des Eingangskondensators C1 geführt ist. Während des Lampenbetriebs sind die Anschlüsse 2 und 3 der Ladebuchse B elektrisch leitend miteinander verbunden, so daß der Emitter des Transistors T am Minuspol der Spannungsquelle anliegt. Im Ladebetrieb leuchtet die Leuchtdiode D4 und die Energiezufuhr zur Lampe L findet selbst bei geschlossenem Schalter S nicht statt. Während des Nachladens des Akkumulators wird die elektrisch leitende Verbindung zwischen den Anschlüssen 2 und 3 der Ladebuchse B und damit die Verbindung zwischen dem Emitter des Schalttransistors T und dem Minuspol der Spannungsquelle unterbrochen. Die Schaltung arbeitet nach demselben Funktionsprinzip wie die des bereits erläuterten ersten Ausführungsbeispiels.Furthermore, the circuit arrangement contains a charging socket B, which allows the battery to be recharged. The connection 1 of the charging socket B is connected via a diode D3 and an ohmic resistor R4 to the positive pole of the voltage source and via a light-emitting diode D4 and via an ohmic resistor R5 to the minus pole of the input capacitor C1. The connection 2 of the charging socket B is connected to the emitter connection of the transistor T, while the connection 3 of the charging socket B is led to the negative pole of the voltage source and to the negative pole of the input capacitor C1. During lamp operation, the connections 2 and 3 of the charging socket B are connected to one another in an electrically conductive manner, so that the emitter of the transistor T is present at the negative pole of the voltage source. In charging mode, the LED D4 lights up and the energy supply to the lamp L does not take place even when the switch S is closed. During the recharging of the battery, the electrically conductive connection between the terminals 2 and 3 of the charging socket B and thus the connection between the emitter of the switching transistor T and the negative pole of the voltage source is interrupted. The circuit works according to the same functional principle as that of the first exemplary embodiment already explained.

Eine geeignete Dimensionierung der in diesem Ausführungsbeispiel verwendeten Bauteile kann der Tabelle 2 entnommen werden.A suitable dimensioning of the components used in this exemplary embodiment can be found in Table 2.

Die Erfindung beschränkt sich nicht auf die näher erläuterten Ausführungsbeispiele. So ist es zum Beispiel möglich, in den Ausführungsbeispielen eins und drei, beide Lampenelektroden mit einem Heizstrom zu beaufschlagen, indem auf ein Kurzschließen der ersten Lampenelektrode E1 verzichtet wird. Tabelle 1 Dimensionierung der Schaltungsanordnung gemäß des ersten und zweiten Ausführungsbeispiels Ferrit-Transformator EF16 N1, N3 25 Wicklungen N2 420 Wicklungen R1 47 Ω R2 1 KΩ C1 100 µ C2, C5 10 nF C3 22 nF C4, C4' 100 pF T D882-Y D1, D2 1N1937 Tabelle 2 Dimensionierung der Schaltungsanordnung gemäß des dritten Ausführungsbeispiels Ferrit-Transformator EF16 N1, N3 25 Wicklungen N2 420 Wicklungen R1 47 Ω R2 560 Ω R3 1 KΩ R4 47 Ω; 0,8W R5 470 Ω C1 100 µ; 10 V C2, C5 10 nF C3 22 nF C4 150 pF; 1 KV T D882-Y D1, D2 1N1937 D3 1N4001 D4 LED, rot The invention is not limited to the exemplary embodiments explained in more detail. For example, in embodiments one and three, it is possible to apply heating current to both lamp electrodes by dispensing with short-circuiting of the first lamp electrode E1. Table 1 Dimensioning of the circuit arrangement according to the first and second exemplary embodiments Ferrite transformer EF16 N1, N3 25 windings N2 420 windings R1 47 Ω R2 1 KΩ C1 100 µ C2, C5 10 nF C3 22 nF C4, C4 ' 100 pF T D882-Y D1, D2 1N1937 Dimensioning of the circuit arrangement according to the third embodiment Ferrite transformer EF16 N1, N3 25 windings N2 420 windings R1 47 Ω R2 560 Ω R3 1 KΩ R4 47 Ω; 0.8W R5 470 Ω C1 100 µ; 10 V C2, C5 10 nF C3 22 nF C4 150 pF; 1 KV T D882-Y D1, D2 1N1937 D3 1N4001 D4 LED, red

Claims (7)

Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle, wobei die Schaltungsanordnung als Eintakt-Sperrwandler ausgebildet ist, der einen Transistor (T) und einen Transformator besitzt, wobei die Primärwicklung (N1) des Transformators in Reihe zur Schaltstrecke des Transistors (T) geschaltet ist, und wobei der Transformator eine Sekundärwicklung (N2) für die Zünd- bzw. für die Betriebsspannung der Lampe (L) sowie eine Rückkopplungswicklung (N3) zur Ansteuerung der Steuerelektrode des Transistors (T) aufweist,
dadurch gekennzeichnet, daß ein Anschluß der Sekundärwicklung (N2) des Transformators über eine erste Diode (D1) mit einer ersten Lampenelektrode (E1) verbunden ist, der andere Anschluß der Sekundärwicklung (N2) mit der Primärwicklung (N1) und über eine zweite Diode (D2) mit der zweiten, heizbaren Lampenelektrode (E2) verbunden ist.Circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source, the circuit arrangement being designed as a single-ended flyback converter which has a transistor (T) and a transformer, the primary winding (N1) of the transformer being connected in series with the switching path of the transistor (T) and the transformer has a secondary winding (N2) for the ignition or operating voltage of the lamp (L) and a feedback winding (N3) for driving the control electrode of the transistor (T),
characterized in that one connection of the secondary winding (N2) of the transformer is connected to a first lamp electrode (E1) via a first diode (D1), the other connection of the secondary winding (N2) to the primary winding (N1) and via a second diode ( D2) is connected to the second, heatable lamp electrode (E2). Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle nach Anspruch 1, dadurch gekennzeichnet, daß die Schaltungsanordnung einen Kondensator (C4) enthält, der die erste Lampenelektrode (E1) mit der zweiten Lampenelektrode (E2) verbindet.Circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to Claim 1, characterized in that the circuit arrangement contains a capacitor (C4) which connects the first lamp electrode (E1) to the second lamp electrode (E2). Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle nach Anspruch 1, dadurch gekennzeichnet, daß die Schaltungsanordnung einen Kondensator (C4') besitzt, der parallel zur ersten Diode (D1) geschaltet ist.Circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to Claim 1, characterized in that the circuit arrangement has a capacitor (C4 ') which is connected in parallel with the first diode (D1). Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle nach Anspruch 1, dadurch gekennzeichnet, daß die Schaltungsanordnung einen variablen Dimmwiderstand (R3) enthält, der ein Dimmen der Lampe (L) ermöglicht.Circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to Claim 1, characterized in that the circuit arrangement contains a variable dimming resistor (R3) which enables the lamp (L) to be dimmed. Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle nach Anspruch 4, dadurch gekennzeichnet, daß der Dimmwiderstand (R3) mit der Rückkopplungswicklung (N3) und über weitere Widerstände (R1, R2) mit der Steuerelektrode des Transistors (T) verbunden ist.Circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to Claim 4, characterized in that the dimming resistor (R3) is connected to the feedback winding (N3) and, via further resistors (R1, R2), to the control electrode of the transistor (T). Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle nach Anspruch 1, dadurch gekennzeichnet, daß die Niedervolt-Spannungsquelle aus einem Akkumulator besteht und die Schaltungsanordnung eine Ladebuchse (B) enthält, die ein Nachladen des Akkumulators erlaubt.Circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to claim 1, characterized in that the low-voltage voltage source consists of an accumulator and the circuit arrangement contains a charging socket (B) which allows the accumulator to be recharged. Schaltungsanordnung zum Betrieb einer Niederdruckentladungslampe an einer Niedervolt-Spannungsquelle nach Anspruch 1, dadurch gekennzeichnet, daß beide Lampenelektroden vor dem Zünden der Lampe mit einem Heizstrom beaufschlagt werden.Circuit arrangement for operating a low-pressure discharge lamp on a low-voltage voltage source according to claim 1, characterized in that a heating current is applied to both lamp electrodes before the lamp is ignited.
EP94117877A 1993-11-25 1994-11-11 Low voltage circuit for operating a low pressure discharge lamp Expired - Lifetime EP0655880B1 (en)

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EP0845927A2 (en) * 1996-11-27 1998-06-03 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Circuit for operating low pressure discharge lamps with a low voltage source
EP1915035A3 (en) * 2006-09-26 2008-05-07 Sander Elektronik AG Method and device for powering a fluorescent lamp in emergency illumination

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EP0845927A3 (en) * 1996-11-27 1999-06-30 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Circuit for operating low pressure discharge lamps with a low voltage source
EP1915035A3 (en) * 2006-09-26 2008-05-07 Sander Elektronik AG Method and device for powering a fluorescent lamp in emergency illumination

Also Published As

Publication number Publication date
EP0655880B1 (en) 1998-07-01
CA2135549A1 (en) 1995-05-26
DE59406367D1 (en) 1998-08-06
DE9318071U1 (en) 1995-03-23
JP3010988U (en) 1995-05-09
CA2135549C (en) 2000-06-06
US5461286A (en) 1995-10-24
HK1010444A1 (en) 1999-06-17

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